Outline

Introduction: Elderly patients receive the highest share of all drugs in western countries. Several of these drugs are classified as potentially inappropriate medication (PIM) for elderly people due to their increased risk for causing adverse drug reactions (ADR). Based on the German PIM list, which has been adapted to the German market and prescribing patterns [Holt et al. Dtsch Arztebl Int 2010], we aimed to analyze PIM utilisation in two cohorts of elderly outpatients, namely the getABI-cohort [Diehm et al. Circulation 2009] and a cohort of stroke patients from the Stroke Database North-West-Germany [Schneider et al. Nervenheilkunde 2009].

Methods: Demographic data, medical history, current medication and self-reported ADR from 1937 patients (getABI-cohort: mean Â± SD 78Â±4 years, 53% females) and 545 patients (Stroke-cohort: mean Â± SD 71Â±11 years, 40% females) were collected in telephone and face to face interviews, respectively. Medication use was evaluated with regard to polypharmacy, frequency of PIM and their relationship to ADR. Data were transferred and analysed in a Microsoft Access Database and via SAS (version 9.1).

Results: In both cohorts the average number of prescribed daily medications came to 6Â±3 drugs. 60% of getABI-patients and 69% of stroke patients used five or more drugs. In 310 (16% – getABI) and 113 (21% – stroke) patients at least one PIM was prescribed. 14% and 9% of the patients, resp., used two or more PIM. The most commonly observed PIM in the getABI-cohort were acetyldigoxin, doxazosine, and sotalol (11%, 9%, 7% of all PIM, respectively). Patients of the Stroke-cohort used acetyldigoxin, piracetam, and amitriptylin most frequently (11%, 10%, 7% of all PIM respectively). 64% of the getABI-patients had at least one possible drug-drug-interaction (DDI), 22% of them used high-risk combinations.

Discussion and conclusion: Polypharmacy and drug-drug interactions occur frequently in elderly German patients. The prevalence of PIM is comparable with findings from a cross-national survey of eight European countries with an average PIM prevalence of 19.8% [FialovÃ¡ et al. JAMA 2005]. Further analyses with regard to the relationship between multimorbidity, clinical functioning, polypharmacy, PIM and ADR will be performed.